It’s the year of the mega deal.

Charter Communications Inc. (CHTR) and Time Warner Cable Inc. (TWC) have announced a $79 billion merger.

Kraft and Heinz combined to form The Kraft Heinz Co. (KHC), the fifth-largest food and beverage company in the world.

Insurance companies ACE Limited (ACE) and The Chubb Corp. (CB) are getting married in a transaction valued at $29 billion.

And Dell’s $67 billion offer for EMC Corp. (EMC) is set to be the largest technology sector acquisition in history.

The list goes on and on.

So far this year, there have been 33 North American merger & acquisition (M&A) deals announced with values greater than $10 billion. Year to date, North American M&A deal volume has totaled an eye-popping $1.67 trillion.

Ladies and gentlemen, welcome to merger mania.

The following chart helps put this year’s activity into perspective:

I’ve adjusted the historical M&A volume data for inflation, so the dollar figures are directly comparable.

We still have nearly two months to go before the year is over, and we’ve already surpassed the volume levels of 2006 and 2007. Also, the 2015 year-to-date deal flow total doesn’t include proposed deals with unspecified terms.

For instance, Pfizer Inc. (PFE) is reportedly in talks to acquire Allergan plc (AGN) in a super-mega deal that could be upwards of $180 billion. And there are other deals in the works that should be formally announced before the end of the year.

Before it’s all said and done, this year’s gargantuan deal volume will swell even further.

Indeed, we’re witnessing a bona fide merger mania.

Hold off on the champagne, though. Frenetic M&A activity represents late-cycle behavior that typically corresponds with major stock market tops. As such, I’ll make a guarantee…

At some point before 2020, M&A activity will nearly grind to a halt. Instead of making acquisitions, many companies will be shedding assets to survive the downturn.

Even companies that are willing and able to do deals will find them difficult to accomplish because credit availability will have dried up, thereby limiting acquirers’ ability to finance takeovers.

Get ready, because we’ll likely see an annual level of M&A volume commensurate with that of 2003 and 2009 in one of the next five years.

The financial markets will be in disarray and investors will be wondering why they didn’t heed the warning signs.

Now is the time to prepare for that eventuality, rather than in the throes of the next correction or bear market.

Safe (and high-yield) investing,

Alan Gula, CFA